Customer interaction has imo always been one of the most important parts in good engineering organizations. Delegating that to Product Managers adds unnecessary friction.

Having spent more hours than I care to count struggling to control my facial expressions in client-facing meetings your assertion that that friction is unnecessary is highly questionable. Having a "face man" who's sufficiently tech literate to ask decent questions manage the soft side of client relations frees up a ton of engineering resources that would otherwise be squandered replying to routine emails.